Helmet shell



FIG. 1 is a front perspective view of a helmet shell showing our new design;

FIG. 2 is a front view of the helmet shell of FIG. 1;

FIG. 3 is a left side view of the helmet shell of FIG. 1;

FIG. 4 is a rear view of the helmet shell of FIG. 1; and,

FIG. 5 is a top view of the helmet shell of FIG. 1. 

CLAIM The ornamental design for a helmet shell, as shown and described. 